1. Field of the Invention
This invention relates to dental implements and, more particularly to such implements which are particularly designed for the filling of root canals with sealing materials.
2. Description of the Related Art
Dental obturators, often referred to as pluggers or, if provided with heating elements, heat carrier/pluggers, are designed for the insertion and packing of tapered gutta percha cones into a previously prepared root canal. My U.S. Pat. No. 5,921,775, describes an endodontic treatment system in which the shaping instruments, irrigation cannulas, filling implements and related materials designed to safely create specific tapers in root canal preparation are provided. All of these various implements are designed with the same taper, preferably one which is greater than the standard ISO taper of 0.02 mm of taper/mm of flute length. My patent describes some of the benefits to be realized from using a taper which is greater than the 0.02 taper (the ISO standard) and also benefits derived from having all of the files and auxiliary implements with the same taper.
In the preparation of a root canal by removing the pulp and shaping the canal to the best configuration for receiving filling materials, such as gutta percha, it is extremely important to control the depth of penetration of root canal files and to limit the depth of penetration to the root tip. In one procedure known in the prior art, as disclosed in U.S. Pat. No. 4,028,810 of Vice, the length of the tooth involved, as well as the length of the root canal, is accurately determined by means of X-rays.
Negotiation files may be used to keep track of the depth of the root tip as the root canal is being enlarged and shaped in preparation for the final step of insertion of the filling material. Various methods are used to limit the depth of penetration to a safe degree. Extreme care must be taken to avoid penetration beyond the root canal which may result in injury and possible infection of the adjacent periodontal tissue and bone structure.
U.S. Pat. No. 4,028,810 of Vice also discloses a handle portion which is adjustably mounted in telescoping relation on the shaft of an elongated working tool. This arrangement provides a means for quickly and accurately adjusting the working length of the tool projecting from the handle.
U.S. Pat. No. 3,911,587 of Forrest et al. discloses the use of reference devices formed with a plurality of blind bores of predetermined depth. These cover the known range of root canal depths, and permit the insertion of an instrument to be used in the procedure by setting the marker on the instrument.
U.S. Pat. No. 4,165,562 of Sarfatti discloses a base and sleeve jointly provided with mating threads to facilitate precise longitudinal adjustment of the file relative to the sleeve. The bottom end of the sleeve is utilized as a stop which abuts the tooth to thereby limit the depth of file penetration.
These and other prior art devices of similar design have a number of disadvantages in use. They are somewhat cumbersome in construction and it is time-consuming to use such that occasionally an endodontist will bypass the step of using such an implement, and work on the root canal directly with the preparation file, sometimes with disastrous results.